? Ultra Low Power, High Sensitivity

GPS-NX01 Receiver User Guide

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? 1. Introduction 1.1 Overview The GPS-NX01 Smart Receiver is an ultra low power GPS receiver based on the proven technology of the NemeriX NJ1030A chipset. The positioning application meets strict needs such as car navigation, mapping, surveying, security, agriculture and so on. Only a clear view of the sky and a power supply are needed. With its ultra low power consumption, the smart receiver tracks up to 16 satellites at a time, re-acquires satellite signals in 1 second (average) and updates position data every second. The GPS-NX01 can be used as a general purpose GPS receiver with NMEA-0183 output. However, its most unique feature is the ability to transfer GPS data (time, date, latitude and longitude) to a wide variety of telescopes that understand the Meade LX200 Command Set or Celestron NexStar Communication Protocol. 1.2 Features The GPS-NX01 provides a host of features that make it easy to use: ? Fast time-to-first-fix and ultra low power consumption ? High performance NemeriX chipset tracks up to 16 satellites in parallel ? Compact design with integrated antenna/receiver ? Rechargeable Lithium cell sustains internal clock and memory (recharges during normal operation) ? One full duplex serial port with selectable baud rates and NMEA messages ? Supports standard NMEA-0183, Meade LX200 and Celestron NexStar communication protocols ? Automatically detects telescope type (Meade, Celestron or none) ? Switches to standard NMEA output after 30 seconds if no telescope is detected ? LED power indicator blinks to indicate receiver status ? Automatic cold start with no user initialization required 1.3 Specifications The GPS-NX01 technical specifications are listed below: ? Size: 47 x 39 x 16 mm (1.9" x 1.5" x 0.6") ? Weight: 70 g (2.5 oz) ? Tracks up to 16 satellites (-152 dBm sensitivity) ? Warm start in 38 seconds (50%), cold start in 45 seconds (50%) ? Position accuracy: 3 meters CEP (50%), 7m (90%) ? Velocity: 0.1 meters/second, without SA ? Time: +/- 100 nanosecond synchronized to GPS time ? Altitude: 18,000 meters (60,000 feet) max ? Velocity: 515 meters / second (1000 knots) max ? Acceleration: 4 G, max ? Interface: RS-232 with 2 m (78") cable (PS/2 Female) ? Baud rate: 9600 (default), 4800, 19200, 38400 ? NMEA-0183 Version 2.2 ASCII output: GPGGA, GPGSA, GPGSV, GPRMC, GPVTG, GPGLL, GPZDA ? Meade LX200 Command Set ? Celestron NexStar Communication Protocol (requires firmware version 2.3, 104.0 or 4.0+) ? Power: 3.6 to 5.5 V @ 35 ma (normal) or 16 ma (sleep mode) ? Backup power: 3V rechargeable lithium cell (350 hours) ? Operating temperature: -40 to +85°C (-40 to +185°F) ? Relative humidity: 5% to 90% non-condensing

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? 2. Hardware Interface The GPS-NX01 includes a low noise, high gain active antenna in a unique waterproof case. Simply connect the PS/2 female connector to one of the optional accessories and link to either your notebook PC, PDA, telescope or other device. For telescope adapter cables refer to www.stargps.ca/cables.htm, other cables are listed and described below:

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? 2.1 GPS-NX01 Connector Standard cable: 2 meters with female PS/2 connector. Pin Assignment of standard PS/2 Din Jack

Pin 1 2 3 4 5 6

Signal Tx (RS-232) +5VDC Tx (TTL) GND Rx (TTL) Rx (RS-232)

2.2 GPS-DB9 Cable Mini Din Female and PS/2 male connector: Cable Length: To GPS-NX01: 1 meter RS-232 to PS/2: 45 cm Mini Din Female connector function definition:

Pin Signal 1 N.C. 2 TX 3 RX 4 N.C. 5 GND 6 N.C. 7 N.C. 8 N.C. 9 N.C. PS/2 composite connector function definition (to PC):

Pin Signal 1 +5VDC 2 N.C. 3 N.C. 4 GND 5 N.C. 6 N.C.

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? 2.3 GPS-USB Cable PS/2 male connector and A Type USB connector: Cable Length: USB to PS/2: 50 cm A Type USB connector function definition:

Pin Signal 1 +5VDC 2 D+ 3 D4 GND

3. USB Driver Installation 3.1 System Requirements Pentium or above and other compatible PC with Windows 98/ME/2000/XP/Vista 3.2 Installation 1. Download and install the USB driver from http://www.stargps.ca/pub/pl2303.zip 2. Plug the USB connector into a USB port on the computer. 3. After the installation is complete, go to and select to verify if a virtual COM port was created. 4. Connect the GPS-NX01 to the GPS-USB cable. 3.3 Important Notice Verify the COM port # to start using your own navigating software. 1. Click menu, select , then enter 2. After entering , select 3. Select 4. Find the and check the Virtual COM Port, which was created by the USB driver. Please note that the Virtual COM Port number might be different from every computer. Before using navigating software, please confirm the COM Port numbers created by your computer and provided by your navigation software. They must be the same Com Port numbers. Otherwise, the navigating software won’t receive the satellite signal for the un-matched COM Port setting.

4. Warranty The GPS-NX01 receiver is warranted to be free from defects in material and functions for one year from the date of purchase. Any failure of this product within this period under normal conditions will be replaced at no charge (excluding shipping costs).

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? Appendix : Software Specification NMEA Protocol The software is capable of supporting the following NMEA message formats: NMEA Message Prefix Format Direction $GPGGA(1)* GPS fix data. Out $GPGLL(0) Geographic position Latitude / Longitude. Out $GPGSA(3)* GNSS DOP and actives satellites Out $GPGSV(3)* Satellites in view. Out $GPRMC(1)* Recommended minimum specific GNSS data. Out $GPVTG(1)* Velocity and track over ground. Out $GPZDA(0) Date and time. Out * The GPS will operate in telescope mode if all NMEA messages are off (this is the default setting). In this mode the GPS attempts to determine the telescope protocol (Meade or Celestron). If no telescope is found after 30 seconds the GPS LED will blink rapidly for 5 seconds and then NMEA output will begin as shown in the above table (0=none, 1=every second, 3=every three seconds). NMEA Extensions The software is capable of supporting the following NMEA extensions: NMEA Message Prefix Format $PNMRX100 Set serial port parameters. $PNMRX101 Navigation initialization $PNMRX103 NMEA message rate control $PNMRX104 LLA navigation initialization $PNMRX106 Set Datum. $PNMRX107 NemeriX messages rate control $PNMRX108 NMEA message sequence control $PNMRX110 Fix Settings $PNMRX111 Software Reset $PNMRX112 Operating Mode Control $PNMRX113 Fix and Extraction control $PNMRX300 Almanac data transfer $PNMRX301 Ephemeris data transfer. $PNMRX302 Ionospheric correction $PNMRX303 UTC Time $PNMRX304 GPS Constellation Health Status $PNMRX600 SW Version report $PNMRX601 ISP mode $PNMRX603 Settings Report

Direction In In In In In In In In In In In In / Out Out Out Out Out Out In Out

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? General NMEA Format The general NMEA format consists of an ASCII string commencing with a ‘$’ character and terminating with a sequence. NMEA standard messages commence with ‘GP’ then a 3-letter message identifier. NemeriX specific messages commence with $PNMRX followed by a 3 digit number. The message header is followed by a comma delimited list of fields optionally terminated with a checksum consisting of an asterix ‘*’ and a 2 digit hex value representing the checksum. There is no comma preceding the checksum field. When present, the checksum is calculated as a bytewise exclusive of the characters between the ‘$’ and ‘*’. As an ASCII representation, the number of digits in each number will vary depending on the number and precision, hence the record length will vary. Certain fields may be omitted if they are not used, in which case the field position is reserved using commas to ensure correct interpretation of subsequent fields. The tables below indicate the maximum and minimum widths of the fields to allow for buffer size allocation. $GPGGA This message transfers global positioning system fix data. The $GPGGA message structure is shown below: Field Format Min Max Notes chars chars Message ID $GPGGA 6 6 GGA protocol header. UTC Time hhmmss.sss 2,2,2.3 2,2,2.3 Fix time to 1ms accuracy. Latitude float 3,2.4 3,2.4 Degrees * 100 + minutes. N/S Indicator char 1 1 N=north or S=south Longitude float 3,2.4 3,2.4 Degree * 100 + minutes. E/W Char 1 1 E=east or W=west indicator Position Fix Indictor

Int

1

1

0: Fix not available or invalid. 1: GPS SPS mode. Fix available.

Satellites Used

Int

2

2

Number of satellites used to calculate fix.

HDOP MSL Altitude Units Geoid Separation Units Age of Differential Corrections Diff Reference Corrections Checksum Message terminator

Float Float Char Int

1.1 1.1 1 (0) 1

3.1 5.1 1 4

Horizontal Dilution of Precision. Altitude above mean seal level M Stands for “meters”. Separation from Geoid, can be blank.

Char int

1 (0) 1

1 5

M Stands for “meters”. Age in seconds Blank (Null) fields when DGPS is not used.

int

4

4

0000.

*xx

(0) 3 2

3 2

2 digits. ASCII 13, ASCII 10.

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? $GPGLL This message transfers Geographic position, Latitude, Longitude, and time. The $GPGLL message structure is shown below: Field Format Min chars Max chars Notes Message ID $GPGLL 6 6 GLL protocol header. Latitude Float 1,2.1 3,2.4 Degree * 100 + minutes. N/S Indicator Char 1 1 N=north or S=south. Longitude Float 1,2.1 3,2.4 Degree * 100 + minutes. E/W indicator Character 1 1 E=east or W=west. UTC Time hhmmss.sss 1,2,2.1 2,2,2.3 Fix time to 1ms accuracy. Status Char 1 1 A Data Valid. V Data invalid. Mode Indicator Checksum Message terminator

Char *xx

1 (0) 3 2

1 3 2

A Autonomous 2 digits. ASCII 13, ASCII 10.

$GPGSA This message transfers DOP and active satellites information. The $GPGSA message structure is shown below: Field Format Min chars Max Notes chars Message ID $GPGSA 6 6 GSA protocol header. Mode Char 1 1 M Manual, forced to operate in selected mode. A Automatic switching between modes. Mode Int 1 1 1 Fix not available. 2 2D position fix. 3 3D position fix. Satellites Used Satellites Used … Satellites Used PDOP HDOP VDOP Checksum Message terminator

Int Int . Int Float Float Float *xx

2 2 .. 2 1.1 1.1 1.1 0 2

2 2 .. 2 3.1 3.1 3.1 3 2

SV on channel 1. SV on channel 2. .. SV on channel 12.

2 digits ASCII 13, ASCII 10

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? $GPGSV This message transfers information about satellites in view. The $GPGSV message structure is shown below. Each record contains the information for up to 4 channels, allowing up to 12 satellites in view. In the final record of the sequence the unused channel fields are left blank with commas to indicate that a field has been omitted. Field Format Min Max Notes chars chars Message ID $GPGSV 6 6 GSA protocol header. Number of Int 1 1 Number of messages in the message messages sequence from 1 to 3. Message number

Int

1

1

Sequence number of this message in current sequence, form 1 to 3.

Satellites in view Satellite Id Elevation Azimuth SNR

Int Int Int Int Int

1 2 1 1 (0) 1

2 2 3 3 2

Number of satellites currently in view. Satellite vehicle 1. Elevation of satellite in degrees. Azimuth of satellite in degrees. Signal to noise ration in dBHz, null if the sv is not in tracking.

Satellite Id Elevation Azimuth SNR

Int Int Int Int

2 1 1 (0) 1

2 3 3 2

Satellite vehicle 2. Elevation of satellite in degrees. Azimuth of satellite in degrees. Signal to noise ration in dBHz, null if the sv is not in tracking.

Satellite Id Elevation Azimuth SNR

Int Int Int Int

2 1 1 (0) 1

2 3 3 2

Satellite vehicle 3. Elevation of satellite in degrees. Azimuth of satellite in degrees. Signal to noise ration in dBHz, null if the sv is not in tracking.

Satellite Id Elevation Azimuth SNR

Int Int Int Int

2 1 1 (0) 1

2 3 3 2

Satellite vehicle 4. Elevation of satellite in degrees. Azimuth of satellite in degrees. Signal to noise ration in dBHz, null if the sv is not in tracking.

Checksum Message terminator

*xx

(0) 3 2

3 2

2 digits. ASCII 13, ASCII 10.

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? $GPRMC This message transfers recommended minimum specific GNSS data. The $GPRMC message format is shown below. Field Format Min chars Max chars Notes Message ID $GPRMC 6 6 RMC protocol header. UTC Time hhmmss.sss 1,2,2.1 2,2,2.3 Fix time to 1ms accuracy. Status char 1 1 A Data Valid. V Data invalid. Latitude N/S Indicator Longitude E/W indicator Speed over ground Course over ground Date Magnetic variation E/W indicator Mode Checksum Message terminator

Float Char Float Char Float Float ddmmyy Blank Blank Char *xx

1,2.1 1 1,2.1 1 1,1 1.1 2,2,2 (0) (0) 1 (0) 3 2

3,2.4 1 3,2.4 1 5.3 3.2 2,2,2 (0) (0) 1 3 2

$GPVTG This message transfers Velocity, course over ground, message format is shown below. Field Format Min chars Max chars Message ID $GPVTG 6 6 Course (true) Float 1.1 3.2 Reference Char 1 1 Course (magnetic) Float 1.1 3.2 Reference Char 1 1 Speed Float 1.1 4.2 Units Char 1 1 Speed Float 1.1 4.2 units Char 1 1 Mode Char 1 1 Checksum *xx (0) 3 3 Message terminator 2 2

Degrees * 100 + minutes. N=north or S=south. Degrees * 100 + minutes. E=east or W=west. Speed over ground in knots. Course over ground in degrees. Current date. Not used. Not used. A Autonomous 2 digits. ASCII 13, ASCII 10.

and ground speed. The $GPVTG Notes VTG protocol header. Measured heading in degrees. T = true heading. Measured heading (blank). M = magnetic heading. Speed in knots. N = knots. Speed K = Km/h. A Autonomous 2 digits. ASCII 13, ASCII 10.

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? $GPZDA This message transfers UTC Time and Date. Since the latency of preparing and transferring the message is variable, and the time does not refer to a particular position fix, the seconds precision is reduced to 2 decimal places. The $GPZGA message format is shown below. Field Format Min chars Max Notes chars Message ID $GPZDA 6 6 ZDA protocol header. hhmmss UTC time 2,2,2.2 2,2,2.2 00000000.00 to 235959.99 .ss UTC day UTC month UTC Year Local zone hours

dd

Local zone minutes Checksum Message terminator

Unsigned 2 *xx (0) 3 2

2 2 4 (-)2

mm yyyy

Int

2 2 4 (-)2

01 to 31, day of month. 01 to 12. 1989-9999. Offset of local time zone (-13) to 13. 2

3 2

2 digits. ASCII 13, ASCII 10.

Extensions Specification For all $PNMRX messages it is possible to configure an alternative string to replace the NMRX part, the node always responds to the $PNMRX strings and can be configured to generate and respond to the alternative string.

$PNMRX100, Set serial port mode This message is sent to control the serial communications port parameters. The $PNMRX100 message format is shown below. Field Format Min chars Max chars Notes Message ID $PNMRX100 6 6 PNMRX100 protocol header. Protocol Char 1 1 0 NMEA mode 1 NemeriX Binary Mode (under dev) Baud Int 4 6 1200. 2400. 4800. 9600. 19200. 38400. 57600. Parity Char 1 1 0. None. 1. Odd. 2. Even. Checksum *xx (0) 3 3 2 digits. Message terminator



2

2

ASCII 13, ASCII 10.

Example: $PNMRX100,0,4800,0*xx : sets the UART baud rate to 4800 bps and no parity.

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? $PNMRX101, Navigation Initialization This message is sent to initialize navigation parameters to speed up initial acquisition time. The $PNMRX101 message format is shown below. Field Format Min Max Notes chars chars Message ID $PNMRX101 6 8 PNMRX101 protocol header. ECEF_X Int (-)7 (-)7 Signed ECEF x co-ordinate in meters ECEF_Y Int (-)7 (-)7 Signed ECEF y co-ordinate in meters ECEF_Z Int (-)7 (-)7 Signed ECEF z co-ordinate in meters Clock offset Int (0) 1 6 Clock offset of GPS receiver, in [Hz x 100] wrt L1. This changes the clock bias stored in the settings not the actual clock bias used by the system. A cold start is necessary, in order to use this value. Time of week Week number Channel count Checksum Message terminator

Int

1

6

Offset from start of week in seconds

Int

1

4

GPS week number

Int

1

2

*xx

(0) 3 2

3 2

Maximum number of TM to be used. Min 12, max 16. 2 digits. ASCII 13, ASCII 10.

- If used, all three X,Y, and Z components of the ECEF position must be provided, otherwise the message is declared invalid as a whole - Modifying the ECEF coordinates triggers a software system reset after successful execution of the message Examples: $PNMRX101,,,,,,,,8,*xx : Executes a factory reset $PNMRX101,-742507,-5462738,3196706,,,,,,*xx: Sets the receiver position to ECEF (,,) and executes a software reset $PNMRX101,,,,,,,,4,*xx : Sets the fix procedure mode the cold start. This will be valid after each reset, until this value is changed.

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? $PNMRX103, NMEA rate control This message is sent to enable or pause the output of an NMEA message and to determine its output rate. The sequence of the output sequence is determined by the $PNMRX107 message. The $PNMRX103 message format is shown below. The rate of each message can individually be set. If ‘0’ is used, the output of the message is skipped (according to the message sequence). The message length is limited to 80 characters, in the event that the message length would exceed 80 characters it is divided into 2 messages. This message is supported also in a variable length format, where only the necessary fields are used. Field Format Min Max Notes chars chars Message ID $PNMRX103 8 8 PNMRX103 protocol header. Mask ID Int 3 3 Mask identifier: possibilities are GGA GLL GSA GSV RMC VTG ZDA ALL (applies to all messages)

Mask value

Int

1

1

Mask ID Checksum Message terminator

Int *xx

2 (0) 3 2

2 3 2

Output rate in seconds (0=paused) Mask identifier. 2 digits. ASCII 13, ASCII 10.

Examples: $PNMRX103, GSV, 2,GGA, 1,ZDA, 0*xx: GSV is output every 2s, GGA every 1s and no ZDA. $PNMRX103, GSV, 2,GGA, 1,ZDA, 0,,,,,,,,,*xx : same as above, but using a fixed length message $PNMRX103, ALL, 2*xx: all messages are output every 2s. $PNMRX103, ALL, 0*xx: skips all messages.

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? $PNMRX104, LLA navigation initialization This message enables the receiver to be initialized using LLA data to speed up satellite acquisition. The first 4 values defining the position (if used) must be all present in the message. Otherwise the whole massage is considered invalid. Field Format Min Max Notes chars chars Message ID $PNMRX104 8 8 PNMRX104 protocol header. (under dev.) Latitude Float 1,2.1 3,2.4 Degrees * 100 + minutes. (under dev.) N/S Char 1 1 N=north or S=south. (under dev.) Indicator Latitude Float 1,2.1 3,2.4 Degrees * 100 + minutes. (under dev.) E/W Char 1 1 E=east or W=west. (under dev.) Indicator Altitude Int (-) 1 (-) 6 Altitude above MSL, in meters. Clock offset Int (0) 1 6 Clock offset of GPS receiver. This changes the clock bias stored in the settings, not the actual clock bias used by the system. A cold start is necessary, in order to use this value. Time of week Week number Channel count Checksum Message terminator

Int

1

6

Int

1

4

Int

1

2

*xx

(0) 3 2

3 2

Offset from start of week in seconds. (under dev.) GPS week number. Maximum number of TM to be used. Min12, max 16. 2 digits. ASCII 13, ASCII 10.

- If used, all five components (Lat, N/S, Long E/W, alt) of the LLA position must be provided, otherwise the message is declared invalid as a whole - Modifying the LLA coordinates triggers a software system reset after successful execution of the message.

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? $PNMRX106, Datum This message defines the conversion model used for mapping the ECEF coordinates into the LLA ones. The default transformation uses WGS84 approximation. The transformation method can be changed into one using a reference Ellipsoid combined with a local datum, to obtain a specific estimation of the local earth geometry. Once the datum has been changed it will be applied to all LLA data, including the LLA navigation initialization Data. This message enables the receiver to be configured to use map datum from an internal table, or datum supplied as part of the message. Field Format Min Max Notes chars chars Message ID $PNMRX106 6 8 PNMRX106 protocol header. Correction Unsigned 1 1 If 1 apply EGM96 geoid correction (warning: Mode should be applied only when Map Datum is equal to 216). If 0 there is no EGM96 geoid correction. Map Datum Int (0) 1 3 Reference number of the appropriate map datum to apply. 0-218 Map datum from internal table 500 User defined Datum Dx

Int

(-)5

X offset in meters (-9999 to 9999)

(-)5

Y offset in meters (-9999 to 9999)

(-)5

Z offset in meters (-9999 to 9999)

Int

(0) (-)1 (0) (-)1 (0) (-)1 (0) 1

Dy

Int

Dz

Int

Iflat

8

Inverse flatness of reference geode. The value to be used is (IFlat – 290) * 1000000). The value must be in the range [6000000, 12000000]

Majora

Int

(0) 1

8

Checksum Message terminator

*xx

(0) 3 2

3 2

Semi major axis of reference geode. The values to be used is (MajorA – 6370000) * 1000). The value must be in the range [6000000, 9000000] 2 digits. ASCII 13, ASCII 10.

Examples: $PNMRX106, 0,500, -2000,-2000,-2000,8257224,8137000*00*xx : User defined Datum $PNMRX106, 1,216,,,,,*xx : WGS 84 Datum

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? $PNMRX107, Messages rate control This message is sent to set the automatic update rate, and to configure which messages will be automatically output, it is also sent from the node to report which messages are currently configured for automatic transmission. The $PNMRX107 message format is shown below. This message can be used to enable and disable multiple messages by including up to 4 message codes and associated fields in each $PNMRX107 message. The message length is limited to 80 characters, in the event that the message length would exceed 80 characters it is divided into 2 messages. This message is supported also in a variable length format, where only the necessary fields are used. Field Format Min Max Notes chars chars Message ID $PNMRX107 8 8 PNMRX107 protocol header. Message code Char 3 3 Determines which message is being configured. 300 PNMRX300 Almanac Data 301 PNMRX301 Ephemeris Data 302 PNMRX302 lonospheric corrections 303 PNMRX303 UTC Time 304 PNMRX304 GPS constellation health ALL Applies to all messages Mode

Int

1

1 0 Disable message 1 Send message now 2 Send message on change 3 Send message now and on change

Checksum Message terminator

*xx

(0) 3 2

3 2

2 digits. ASCII 13, ASCII 10.

Examples: $PNMRX107,300,1*xx : Output the almanac stored in NVRAM $PNMRX107,301,2*xx : Output Ephemeris will be output on change $PNMRX107,ALL,2*xx : Output all output messages (300,301,302,303,304)

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? $PNMRX108, NMEA message sequence This message is used to set the sequence used to output the NMEA messages. All messages in the list are set to be output with a default output rate. The messages that are not included are disabled. Once the sequence is defined, individual settings for the messages can be changed by means of the $PNMRX103 message. This message is supported also in a variable length format, where only the necessary fields are used. Field Format Min chars Max chars Notes Message ID $PNMRX108 6 8 PNMRX108 protocol header. Mask ID Int 3 3 Mask identifier: possibilities are GGA GLL GSA GSV RMC VTG ZDA

Mask ID Checksum Message terminator

Int *xx

3 (0) 3 2

3 3 2

Mask Identifier. 2 digits. ASCII 13, ASCII 10.

Example: $PNMRX108,GGA,GLL,GSA*xx : Enables the GGA, GLL and GSA in this sequence, output every second. All other messages are disabled

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? $PNMRX110, Fix Settings This message is used to set various settings and masks which control how the software will behave in relationship to the satellites in view, for example a mask can be set for the minimum satellite elevation, minimum SNR etc. The message consists of a varying number of fields depending on the number of masks to be set. Each mask setting consists if a mask identifier and new value pair. The $PNMRX110 message format is shown below. PNMRX110 field list Min Max Notes chars chars 6 8 PNMRX110 protocol header. 2 2 Mask identifier, see below. 1 8 New value for mask, dependent on the preceding field, see below.

Field

Format

Message ID Mask ID Value

$PNMRX110 Int Variant

Mask ID Value

Int Variant

2 1

2 8

Checksum Message terminator

*xx

(0) 3 2

3 2

Mask Id

Mask identifier. New value for mask, dependent on the preceding field. 2 digits. ASCII 13, ASCII 10.

PNMRX110 Mask Field interpretation format width units Int: unsigned 2:2 Hours : Miuntes

mask Local Time Zone

0 1

1

Maximum PDOP

Unsigned

4

x10, [0-100]

Maximum HDOP

Unsigned

4

x10, [0-100]

Maximum VDOP

Unsigned

4

x10, [0-100]

Minimum SNR

Unsigned

2

dB/Hz, [20-45]

Minimum Elevation

Unsigned

2

Degrees, [0-90]

Noise Floor

Unsigned

4

-, [400-1000]

Navigation Mode 1

1 Unsigned

1

1 = Auto (hold alt) 2 = 2D Mode 4 = 3D Mode (calc alt)

Unsigned

6

Meters above MSL

Boolean

1

Unsigned

6

0 = Auto 1 = Static Meters.

2 1

3 4 5 6 7 8 9 10

1

2D Mode Altitude 1

Navigation Mode 2 Maximum Altitude

Examples: $PNMRX110,0,-2:0*xx : Set the local time to –2 hours 0 minutes. $PNMRX110,4,35*xx : Set the minimum SNR to 35 PixSoft Inc. Tel: +1.204.885.4936 Fax: +1.204.895.4173 E-mail: [email protected] 18

? $PNMRX111, Software reset This message is used to reset the systems. If the message is sent without parameters the receiver reboots according to the fix procedure (hot, warm or cold) configured with the PNMRX101 or PNMRX104 messages. A second parameter can optionally be used to specify which actions are executed after the reset. If the last bit field is set to ‘1’, then the actions are repeated permanently at each reset, until this bit is cleared. Field Format Min Max Notes chars chars Message ID $PNMRX111 6 8 PNMRX111 protocol header. Invalidate Integer OR 1 7 If integer, the bit field have the following parameter String meaning (the action described is executed if the bit is 1): Field Action 0 Reload settings from Flash 1 Clear almanac data and don’t load if from flash 2 Clear Ephemeris data 3 Clear lonospheric and tropospheric corrections 4 Invalidate stored position 5 Invalidate stored time 6 Copy oscillator offset from Settings 7 Sticky bit –if ‘1’ the action are repeated at each reset If String, the following values are allowed: FACTORY See Section 2.1 for definition. COLD See Section 2.1 for definition. WARM See Section 2.1 for definition. HOT See Section 2.1 for definition.

Checksum Message terminator

*xx

(0) 3 2

3 2

2 digits. ASCII 13, ASCII 10.

Example: $PNMRX111*xx : Resets the system

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? $PNMRX112, Power Mode Control This message is used to configure the operating modes of the receiver. Low power modes can be activated and configured. Low power mode starts to work only after the receiver has a complete and up to date almanac and it can produce the fix. Field Format Min chars Max chars Notes Message ID $PNMRX112 6 8 PNMRX112 protocol header. Operating Mode Int 1 1 0 = Fully Active 1 = LDCM1 OFF period Checksum Message terminator

Int *xx

1 (0) 3 2

2 3 2

RF off time in seconds [5:10] 2 digits. ASCII 13, ASCII 10.

Example: $PNMRX112,1,5*xx : enable low power mode (with 5 seconds off time between 2 fixes)

$PNMRX113, GPS Core Activity Control This message is used to disable GPS Core activities (data extraction and fix generation) on the node. The goal of this message is to disable these two functions when they need to be overwritten by external values for test purpose. A reset message must be set after the PNMRX113 in order to resume operation. For instance if a different almanac needs to be downloaded to the receiver then, data extraction must be disabled, then the new almanac can be downloaded. A reset command will then be used to restore operation with hen new almanac. Field Format Min chars Max chars Notes Message ID $PNMRX113 6 8 PNMRX113 protocol header. Checksum *xx (0) 3 3 2 digits. Message terminator 2 2 ASCII 13, ASCII 10. Example: $PNMRX113*xx : Stops GPS Core activities.

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? $PNMRX300, Almanac Data Transfer This message format is used to transfer the almanac data between nodes, it uses a packed hexadecimal format to transfer almanac data for each of the available SV’s. Since the Almanac data is large and can take time to transfer over a slow serial interface, the data is divided into individual messages for each of the SV’s. These messages are transmitted sequentially and can be interleaved with other messages to prevent the Almanac data blocking higher priority messages such as scheduled PVT information. The data for these messages is expressed as signed or unsigned fixed point values which have been scaled from the floating point values used in the position solution. The appropriate scaling factors are included in the table. There is 1 message for each satellite for which data is available. When transmitted these messages are generated in ascending order of SV Id, when being sent to the node these can be sent in any order, each message is individually interpreted and processed. Field Format width scale Notes Message ID $PNMRX300 8 PNMRX300 protocol header. SV Id Int 2 Decimal Satellite vehicle Id from 1 to 32. -21 e Hex 4 16 bit signed int, scale. 2 Health Toa d i

Hex Hex Hex

2 2 4

Omegadot

Hex

4

Root_A Omegazero Perigee Mean

Hex Hex Hex Hex

Mean anomaly af0

Hex Hex

6 6 6 6 6 6

af1

Hex

6

Checksum Message terminator

*xx

(0) 3 2

-19

2 -38

2

-11

2 -23

2 -23

2 -23

2 -23

2 -20

2

-68

2

Bitmap of satellite health. Week Number 16 bit signed int. 16 bit signed int. 24 bit unsigned int. 24 bit signed int. 24 bit signed int. 24 bit signed int. 24 bit signed int. 11 bit signed int. 11 bit signed int. 2 digits. ASCII 13, ASCII 10.

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? $PNMRX301, Ephemeris Data Transfer This message format is used to transfer the ephemeris data between nodes, it uses a packed hexadecimal format to transfer ephemeris data for each of the available SV’s. Since the Ephemeris data is large and can take time to transfer over a slow serial interface, the data is divided into individual messages for each of the SV’s. These messages are transmitted sequentially and can be interleaved with other messages to prevent the Ephemeris data blocking higher priority messages such as scheduled PVT information. The data for these messages is expressed as signed or unsigned fixed point values which have been scaled from the floating point values used in the position solution. The appropriate scaling factors are included in the table. The ephemeris data for each satellite is divided into 3 separate messages with sequence numbers to identify them, the contents of these frames reflects the contents of the appropriate subframes 1,2,3 transmitted from the SV’s. When transmitted these messages are generated in ascending order of SV Id and sequence number, when being sent to the node these can be sent in any order, provided that the 3 messages for any individual satellite are grouped together, each message is individually interpreted and after a group of 3 valid messages for an SV the ephemeris for that SV is updated independently. The 3 message formats are illustrated in the following tables

Field Message ID Satellite vehicle Id Subframe Id Week number Health URA Time Group Delay

PNMRX301 message 1 field list Format width scale Units Notes $PNMRX301 8 PNMRX301 protocol header. Int 2 Decimal satellite vehicle Id from 1 to 32. Int 1 Subframe number 1. Hex 3 Weeks 10 bit week number. Hex 2 6 bits. Hex 1 User range accuracy. -31 Hex 2 Seconds 8 bits. 2

IODC Toc

Hex Hex

3 4

Af2

Hex

2

Af1

Hex

4

Af0

Hex

6

Checksum Message terminator

*xx

(0) 3 2

10 bit integer. 16 bits.

-4

2

-31

2 -43

2 -31

2

2

8 bit signed integer.

sec/sec sec/sec

16 bit signed integer.

Seconds

22 bit signed integer. 2 digits. ASCII 13, ASCII 10.

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? Field Message ID Satellite Vehicle Id

PNMRX301 message 2 field list Format width scale units $PNMRX301 8 Int 2

Subframe Id Iode

Int Hex

1 2

Crs

Hex

4

-5

2 -43

Motion difference (? n)

Hex

4

2

Mean anomaly

Hex

8

2

Cuc

Hex

4

E

Hex

8

Cuc

Hex

4

Root A

Hex

8

Toe

Hex

4

Checksum Message terminator

*xx

(0) 3 2

-31

-29

2

Meters Semicircles/ sec Semicircles

16 bit signed integer.

Radian s

16 bit signed integer.

-33

2 -19

2 4

2

32 bit signed integer.

32 bit signed integer.

2

-29

Notes PNMRX301 protocol header. Decimal satellite vehicle id from 1 to 32. Subframe number 2. 8 bits, lower 8 bits of matching iodc. 16 bit signed integer.

Radian s Meters

16 bit signed integer.

second s

16 bit unsigned integer.

1/4

32 bit signed integer.

2 digits. ASCII 13, ASCII 10.

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? PNMRX301 message 3 field list width scale units 8

Field Message ID

Format $PNMRX301

Satellite Vehicle Id Subframe Id Cic

Int

2

Int Hex

1 4

-29

2 -31

Omega zero

Hex

8

2

Cis

Hex

4

2

-29 -31

I Zero

Hex

4

2

Crc

Hex

4

2

Perigree

Hex

8

Omega dot

Hex

6

Iode

Hex

2

I dot

Hex

4

Checksum Message terminator

*xx

(0) 3 2

-5 -31

2 -43

2

-43

2

Radians

Notes PNMRX301 protocol header. Decimal satellite vehicle id from 1 to 32. Subframe number 3. 16 bit signed integer.

Semi- circles

32 bit signed integer.

radians

16 bit signed integer.

Semi- circles

32 bit signed integer.

Meters

16 bit signed integer.

Semi- circles

32 bit signed integer.

Semi- circles/sec

24 bit signed integer.

Semi- circles/sec

Lower 8 bits of matching iodc. 14 bit signed integer. 2 digits. ASCII 13, ASCII 10.

a

0

$PNMRX302, Ionospheric correction Format width scale units Notes $PNMRX302 8 PNMRX301 protocol header. Int 2 Decimal satellite vehicle id from 1 to 32. -30 Hex 2 2

a

1

Hex

2

2

a

2

Hex

2

2

a

3

Hex

2

2

ß 0

Hex

2

2

ß 1

Hex

2

2

ß 2

Hex

2

2

ß 3

Hex

2

Checksum Message terminator

*xx

(0) 3 2

Field Message ID Satellite Vehicle Id

-27 -24 -24 11 14 16 16

2 2 digits. ASCII 13, ASCII 10.

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? $PNMRX303, UTC time Field Format Message ID $PNMRX303 Satellite Vehicle Id Int

width 8 8

Data – A0

Hex

2

Data – A1

Hex

2

Delta t LS

Hex

2

Tot WNt WNlsf

Hex Hex Hex

2 2 2

DN Delta t LSF

Hex Hex

2 2

NumBlocks TimeOffset

Hex Hex

2 2

Checksum Message terminator

*xx

(0) 3 2

$PNMRX304, GPS Constellation Health Field Format Min chars Message ID $PNMRX304 8 Health Code Char TBD Health Code Char TBD Checksum *xx (0) 3 Message terminator 2

scale

units

Max chars 8 TBD TBD 3 2

Notes PNMRX301 protocol header. Decimal satellite vehicle id from 1 to 32. Constant term of the polynomial First-order term of the polynomial. Delta time due to leap seconds. Reference time for UTC. UTC reference week number Week number at which the leap second becomes effective. Day number B2. Delta time due to leap seconds if leap second is ini the past. Number of 20 year blocks Time offset for current time zone 2 digits. ASCII 13, ASCII 10.

Notes PNMRX110 protocol header. SV health code if ? 0. SV health code if ? 0. 2 digits. ASCII 13, ASCII 10.

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? $PNMRX600, Report Software Version By sending the $PNMRX600*00 string to the receiver, the version of the software is output. $PNMRX601, Enter ISP mode By sending the $PNMRX601*00 string to the receiver, the receiver enters ISP mode. DO NOT USE THIS COMMAND since it is used to reprogram the GPS. $PNMRX603, Settings report By sending the $PNMRX603*00 string to the receiver, the current value of the settings is output. The content of settings is split into 4 messages.

Field Message ID Message Nb Message Sequence (7 times)

PNMRX603 message 0 Format Min Max chars chars $PNMRX603 8 8 Int 1 1 7xInt 1 1

Notes PNMRX603 protocol header. 0 Message Sequence

Message Delay (7 times)

7xInt

1

1

Message Delay

NMRX Message Enabled

Hex

8

8

Nemerix Message Enabled

Uart Settings Checksum Message terminator

Hex *xx

8 (0) 3 2

8 3

Uart settings 2 digits. 2 ASCII 13, ASCII 10.

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? Field

PNMRX603 message 1 Format Min chars

Message ID

$PNMRX603

8

Max chars 8

Message Nb Ionospheric Data A0

Int Hex

1 2

1 2

Ionospheric Data A1

Hex

2

2

Ionospheric correction a 1 coefficient.

Ionospheric Data A2

Hex

2

2

Ionospheric correction a 2 coefficient.

Ionospheric Data A3

Hex

2

2

Ionospheric correction a 3 coefficient.

Ionospheric Data B0

Hex

2

2

Ionospheric correction ß 0 coefficient.

Ionospheric Data B1

Hex

2

2

Ionospheric correction ß 1 coefficient.

Ionospheric Data B2

Hex

2

2

Ionospheric correction ß 2 coefficient.

Ionospheric Data B3

Hex

2

2

Ionospheric correction ß 3 coefficient.

Ionospheric Data Valid

Hex

1

1

Ionospheric Data Valid. If 0 the data are invalid.

Num Blocks

Hex

1

1

Time Offset (Local zone hours)

Int

(-)2

(-)2

Number of 20 year blocks Offset of local time zone (-13) to 13

Time Offset (Local zone minutes)

Int

(-)2

(-)2

Checksum Message terminator

*xx

(0) 3 2

3 2

Notes PNMRX603 protocol header. 1 Ionospheric correction a 0 coefficient.

2 digits. ASCII 13, ASCII 10.

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? Field Message ID Message Nb MaxPDOP MaxHDOP Invalid Sv Min CNO Min Elevation Max TM Max Sv for fix Checksum Message terminator

NMRX603 message 2 Format Min chars Max chars $PNMRX603 8 8 Int 1 1 Float Float Hex 8 Float Float Int 2 Int 2 *xx (0) 3 3 2 2

Message ID

PNMRX603 message 3 Min chars Max chars $PNMRX603 8 8

Message Nb Acq threshold 1

Int Int

1 3

1 8

Acq threshold 2

Int

3

8

Noise floor Kalman Mode Default altitude

Int Hex Int

3 1 1

8 1 8

Checksum Message terminator

*xx

(0) 3 2

3 2

Field

Format

Notes PNMRX603 protocol header. 2

8

2 2 2 digits. ASCII 13, ASCII 10.

Notes PNMRX603 protocol header. 3

2 digits. ASCII 13, ASCII 10.

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? Field

Format

Message ID Message Nb Correction Mode

$PNMRX603 Int Int

PNMRX603 message 4 Min Max Notes chars chars 8 8 PNMRX603 protocol header. 1 1 4 1 1 EGM96 geoid correction

Map Datum

Int

1

8

Reference number of the appropriate map datum to apply

Dx Dy Dz Inverse flatness

Int Int Int Int

1 1 1 1

8 8 8 8

x offset in meters y offset in meters z offset in meters Inverse flatness of reference geode

Major axis Checksum Message terminator

Int *xx

1 (0) 3 2

8 3 2

Semi major axis of reference geode 2 digits. ASCII 13, ASCII 10.

Example: $PNMRX603*xx : Display the content of the Settings stored in NVRam

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